Feature Request: Add a `compat_all()` function

[kdheepak]

Firstly, thanks for writing and maintaining this package. It is now one of those packages that I can't develop without.

Often times when I'm starting a project, I add a number of different packages, e.g. add DataFrames, add CSV, etc. And when I'm ready to share it with co-workers or make it a package on the general registry, I run compat_all() and add the latest version for all the packages I'm using.

I'm always just choosing the latest semantic versions that will prevent breaking changes, i.e. if there's a 1.0, 2.0, 2.1, etc I choose the compat version to be 2. Similarly, I choose 0.2 if there is 0.1, 0.2, 0.2.1, etc. If there's a package that cannot be upgraded to the latest because of a compat bound, I would have to choose one appropriately there.

Is there a way to automatic this? Even something like, "get latest semantic version that doesn't cause breaking changes from Manifest.toml and fix compat" would be super helpful.